How to use the packaging.osx.biplist.__init__.InvalidPlistException function in packaging

def readRoot(self):
        result = None
        self.reset()
        # Get the header, make sure it's a valid file.
        if not is_stream_binary_plist(self.file):
            raise NotBinaryPlistException()
        self.file.seek(0)
        self.contents = self.file.read()
        if len(self.contents) < 32:
            raise InvalidPlistException("File is too short.")
        trailerContents = self.contents[-32:]
        try:
            self.trailer = PlistTrailer._make(unpack("!xxxxxxBBQQQ", trailerContents))
            offset_size = self.trailer.offsetSize * self.trailer.offsetCount
            offset = self.trailer.offsetTableOffset
            offset_contents = self.contents[offset:offset+offset_size]
            offset_i = 0
            while offset_i < self.trailer.offsetCount:
                begin = self.trailer.offsetSize*offset_i
                tmp_contents = offset_contents[begin:begin+self.trailer.offsetSize]
                tmp_sized = self.getSizedInteger(tmp_contents, self.trailer.offsetSize)
                self.offsets.append(tmp_sized)
                offset_i += 1
            self.setCurrentOffsetToObjectNumber(self.trailer.topLevelObjectNumber)
            result = self.readObject()
        except TypeError as e:

elif format == 0b1000:
            result = self.readUid(extra)
        # array
        elif format == 0b1010:
            extra = proc_extra(extra)
            result = self.readArray(extra)
        # set
        elif format == 0b1100:
            extra = proc_extra(extra)
            result = set(self.readArray(extra))
        # dict
        elif format == 0b1101:
            extra = proc_extra(extra)
            result = self.readDict(extra)
        else:    
            raise InvalidPlistException("Invalid object found: {format: %s, extra: %s}" % (bin(format), bin(extra)))
        return result

def check_key(key):
            if key is None:
                raise InvalidPlistException('Dictionary keys cannot be null in plists.')
            elif isinstance(key, Data):
                raise InvalidPlistException('Data cannot be dictionary keys in plists.')
            elif not isinstance(key, StringWrapper):
                raise InvalidPlistException('Keys must be strings.')

result = unpack('>q', data)[0]
            else:
                result = unpack('>Q', data)[0]
        elif byteSize <= 16:
            # Handle odd-sized or integers larger than 8 bytes
            # Don't naively go over 16 bytes, in order to prevent infinite loops.
            result = 0
            if hasattr(int, 'from_bytes'):
                result = int.from_bytes(data, 'big')
            else:
                for byte in data:
                    if not isinstance(byte, int): # Python3.0-3.1.x return ints, 2.x return str
                        byte = unpack_from('>B', byte)[0]
                    result = (result << 8) | byte
        else:
            raise InvalidPlistException("Encountered integer longer than 16 bytes.")
        return result

def check_key(key):
            if key is None:
                raise InvalidPlistException('Dictionary keys cannot be null in plists.')
            elif isinstance(key, Data):
                raise InvalidPlistException('Data cannot be dictionary keys in plists.')
            elif not isinstance(key, StringWrapper):
                raise InvalidPlistException('Keys must be strings.')

self.computeOffsets(value, asReference=True)
            elif isinstance(obj, (list, tuple)):
                size = proc_size(len(obj))
                self.incrementByteCount('arrayBytes', incr=1+size)
                for value in obj:
                    asRef = True
                    self.computeOffsets(value, asReference=True)
            elif isinstance(obj, dict):
                size = proc_size(len(obj))
                self.incrementByteCount('dictBytes', incr=1+size)
                for key, value in iteritems(obj):
                    check_key(key)
                    self.computeOffsets(key, asReference=True)
                    self.computeOffsets(value, asReference=True)
        else:
            raise InvalidPlistException("Unknown object type: %s (%s)" % (type(obj).__name__, repr(obj)))

if byteSize == 1:
            result += pack('>B', obj)
        elif byteSize == 2:
            result += pack('>H', obj)
        elif byteSize == 4:
            result += pack('>L', obj)
        elif byteSize == 8:
            if as_number:
                result += pack('>q', obj)
            else:
                result += pack('>Q', obj)
        elif byteSize <= 16:
            try:
                result = pack('>Q', 0) + pack('>Q', obj)
            except struct_error as e:
                raise InvalidPlistException("Unable to pack integer %d: %s" % (obj, e))
        else:
            raise InvalidPlistException("Core Foundation can't handle integers with size greater than 16 bytes.")
        return result

def check_key(key):
            if key is None:
                raise InvalidPlistException('Dictionary keys cannot be null in plists.')
            elif isinstance(key, Data):
                raise InvalidPlistException('Data cannot be dictionary keys in plists.')
            elif not isinstance(key, StringWrapper):
                raise InvalidPlistException('Keys must be strings.')

return 8
        # UNSIGNED
        elif obj <= 0xFF: # 1 byte
            return 1
        elif obj <= 0xFFFF: # 2 bytes
            return 2
        elif obj <= 0xFFFFFFFF: # 4 bytes
            return 4
        # SIGNED
        # 0x7FFFFFFFFFFFFFFF is the max.
        elif obj <= 0x7FFFFFFFFFFFFFFF: # 8 bytes signed
            return 8
        elif obj <= 0xffffffffffffffff: # 8 bytes unsigned
            return 16
        else:
            raise InvalidPlistException("Core Foundation can't handle integers with size greater than 8 bytes.")